1. Technical Field
The present disclosure relates to a control system of a power transmission system of a vehicle including an electric motor for running the vehicle, which motor is coupled to an input rotating member of a mechanical speed change mechanism such that power can be transmitted between the electric motor and the speed change mechanism.
2. Description of Related Art
A control system of a power transmission system of a vehicle including an electric motor for running the vehicle, and a mechanical speed change mechanism that provides a part of a power transmission path between the electric motor and drive wheels, is well known in the art. For example, a control system of a vehicular drive unit described in Japanese Patent Application Publication No. 2008-207690 (JP 2008-207690 A) is one example of the known system. Regarding the control system of the power transmission system, various proposals have been made to reduce variation or fluctuation in output torque at the time of shifting of the mechanical speed change mechanism so as to reduce shift shock. As disclosed in JP 2008-207690 A, when the mechanical speed change mechanism is shifted down at the time of regeneration by the electric motor for running the vehicle during coasting of the vehicle, regenerative torque of the motor is reduced during an inertia phase in the course of downshifting, so that shift shock is reduced. Also, it is known to perform torque control of the electric motor for running the vehicle during a torque phase in the course of shifting of the mechanical speed change mechanism (namely, perform torque phase compensation control by means of the motor for running the vehicle), so as to suppress or reduce variation in output torque generated during the torque phase, and thus reduce shift shock.